JDBC Access database

I. Conditions of preparation

1. External conditions

• Create a table space first in the database
• Add data to the table you created

1. Code section

• Import a database driver package (JAR)
• Load Database Driver
• Get database connection
• Writing SQL statements
• Pretreatment with Preparestatement
• Set parameters, Parameter 1 represents the first parameter (starting at 1), parameter 2 represents the value of the parameter
• Issue a SQL statement to the database for querying, ExecuteQuery (), and querying to the result set resultset
• Traversing result Sets
• Freeing Resources (connection,resultset,preparestatement)

1. Benefits of Preparestatement

• To achieve the purpose of preprocessing, improve efficiency (as we write code, each write a sentence will be compiled, inefficient, if the use of preparestatement preprocessing, so that if we write to the same SQL statement before, it can not be compiled, So that the efficiency can be increased)

2. Source
4. public static void Main (string[] args) {
6. Declaration link
8. Connection Connection=null;
10. Pretreatment
12. PreparedStatement Preparedstatement=null;
14. Get the result set
16. ResultSet Resultset=null;
18. Load Driver
20. try {
22. Class.forName ("Com.mysql.jdbc.Driver");
24. Get links
26. Connection = Drivermanager.getconnection ("Jdbc:mysql://localhost:3306/jdbc", "root", "123456");
28. Creating SQL statements
30. String sql= "SELECT * from user where username=? ";
32. Pretreatment
34. PreparedStatement = connection.preparestatement (sql);
36. Preparedstatement.setstring (1, "Harry");
38. ResultSet = Preparedstatement.executequery ();
40. while (Resultset.next ()) {
42. System.out.println (resultset.getstring ("id") +resultset.getstring ("username"));
44. }
46. } catch (Exception e) {
48. TODO auto-generated Catch block
50. E.printstacktrace ();
52. }finally{
54. Freeing resources
56. if (resultset!=null) {
58. try {
60. Resultset.close ();
62. } catch (Exception E2) {
64. Todo:handle exception
66. }
68. }if (connection!=null) {
70. try {
72. Connection.close ();
74. } catch (Exception E2) {
76. Todo:handle exception
78. }
80. }if (preparedstatement!=null) {
82. try {
84. Preparedstatement.close ();
86. } catch (Exception E2) {
88. Todo:handle exception
90. }
92. }
94. }
96. }

JDBC Access database